1. Field of the Invention
This invention generally relates to fire equipment apparatus and, more specifically, to a nozzle for rapidly penetrating a fire barrier and delivering water to an area containing superheated gases while minimizing fire backdraft.
2. Background of the Invention
To the fire fighting community, the threat of a potential backdraft condition is of prime concern. More firefighters and civilians are injured or killed each year by the super heated gases and toxins created by the products of combustion, than the fire itself.
Backdrafts are formed when a fire, in an enclosed area, uses most of the available oxygen during its free burning stage. The fire, as this available oxygen is used up, actually darkens down or diminishes in intensity. The smoke and gases that are direct products of combustion rise to the highest levels of the room where they are superheated by the flames. This oxygen poor, superheated gas forces other combustible items in the enclosed area to degas (porassify). This degassing of combustibles increase the toxicity and energy level in this superheated oxygen poor environment. If oxygen is introduced into this atmosphere by current standard fire fighting methods a backdraft erupts with explosive force.
When a door or window is either opened or broken, large quantities of oxygen are sucked into the superheated gaseous environment. When this mixture reaches the explosive range, a flash fire erupts instantly igniting the burning gases outward and setting fire to any combustibles in its path including humans. Since the primary indication of a potentially lethal condition is the sucking inward of immense volumes of air, the word backdraft was coined.
For years, the fire service has known the best way to combat a potential backdraft condition is to either vent the superheated gases at the highest point when possible, or use copious quantities of fog spray to form steam. The injection of a fine fog spray into a superheated environment instantly changes the water droplets to steam. This changing of water to steam increase the volume injected to 27 times its original size. This phenomenon also absorbs vast amounts of energy and in doing so lowers the temperature of the gasses and the room to below its flash point.
The steam vapor also traps the toxic contaminants and they condense and fall to the floor as a sooty slurry. There is a serious flaw in this steam injection method, however, that until now has been unsolved. Currently, to enter this superheated environment in order to inject steam, fire fighters have to risk their lives by opening a door or window enough to direct a fog nozzle into the area of conflagration. Of course oxygen is also let in, and the backdraft scenario is set. The ideal method would be to inject water fog without letting any, or a minimal amount of oxygen into the room.